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	#include "cache.h"
	#include "commit.h"
	#include "tag.h"
	#include "diff.h"
	#include "revision.h"
	#include "progress.h"
	#include "list-objects.h"
	#include "pack.h"
	#include "pack-bitmap.h"
	#include "pack-revindex.h"
	#include "pack-objects.h"
	#include "packfile.h"
	#include "repository.h"
	#include "object-store.h"
	#include "list-objects-filter-options.h"
	#include "config.h"

	/*
	* An entry on the bitmap index, representing the bitmap for a given
	* commit.
	*/
	struct stored_bitmap {
	struct object_id oid;
	struct ewah_bitmap *root;
	struct stored_bitmap *xor;
	int flags;
	};

	/*
	* The active bitmap index for a repository. By design, repositories only have
	* a single bitmap index available (the index for the biggest packfile in
	* the repository), since bitmap indexes need full closure.
	*
	* If there is more than one bitmap index available (e.g. because of alternates),
	* the active bitmap index is the largest one.
	*/
	struct bitmap_index {
	/* Packfile to which this bitmap index belongs to */
	struct packed_git *pack;

	/*
	* Mark the first `reuse_objects` in the packfile as reused:
	* they will be sent as-is without using them for repacking
	* calculations
	*/
	uint32_t reuse_objects;

	/* mmapped buffer of the whole bitmap index */
	unsigned char *map;
	size_t map_size; /* size of the mmaped buffer */
	size_t map_pos; /* current position when loading the index */

	/*
	* Type indexes.
	*
	* Each bitmap marks which objects in the packfile are of the given
	* type. This provides type information when yielding the objects from
	* the packfile during a walk, which allows for better delta bases.
	*/
	struct ewah_bitmap *commits;
	struct ewah_bitmap *trees;
	struct ewah_bitmap *blobs;
	struct ewah_bitmap *tags;

	/* Map from object ID -> `stored_bitmap` for all the bitmapped commits */
	kh_oid_map_t *bitmaps;

	/* Number of bitmapped commits */
	uint32_t entry_count;

	/* If not NULL, this is a name-hash cache pointing into map. */
	uint32_t *hashes;

	/*
	* Extended index.
	*
	* When trying to perform bitmap operations with objects that are not
	* packed in `pack`, these objects are added to this "fake index" and
	* are assumed to appear at the end of the packfile for all operations
	*/
	struct eindex {
	struct object **objects;
	uint32_t *hashes;
	uint32_t count, alloc;
	kh_oid_pos_t *positions;
	} ext_index;

	/* Bitmap result of the last performed walk */
	struct bitmap *result;

	/* "have" bitmap from the last performed walk */
	struct bitmap *haves;

	/* Version of the bitmap index */
	unsigned int version;
	};

	static struct ewah_bitmap lookup_stored_bitmap(struct stored_bitmap st)
	{
	struct ewah_bitmap *parent;
	struct ewah_bitmap *composed;

	if (st->xor == NULL)
	return st->root;

	composed = ewah_pool_new();
	parent = lookup_stored_bitmap(st->xor);
	ewah_xor(st->root, parent, composed);

	ewah_pool_free(st->root);
	st->root = composed;
	st->xor = NULL;

	return composed;
	}

	/*
	* Read a bitmap from the current read position on the mmaped
	* index, and increase the read position accordingly
	*/
	static struct ewah_bitmap read_bitmap_1(struct bitmap_index index)
	{
	struct ewah_bitmap *b = ewah_pool_new();

	ssize_t bitmap_size = ewah_read_mmap(b,
	index->map + index->map_pos,
	index->map_size - index->map_pos);

	if (bitmap_size < 0) {
	error("Failed to load bitmap index (corrupted?)");
	ewah_pool_free(b);
	return NULL;
	}

	index->map_pos += bitmap_size;
	return b;
	}

	static int load_bitmap_header(struct bitmap_index *index)
	{
	struct bitmap_disk_header header = (void )index->map;
	size_t header_size = sizeof(*header) - GIT_MAX_RAWSZ + the_hash_algo->rawsz;

	if (index->map_size < header_size + the_hash_algo->rawsz)
	return error("Corrupted bitmap index (too small)");

	if (memcmp(header->magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE)) != 0)
	return error("Corrupted bitmap index file (wrong header)");

	index->version = ntohs(header->version);
	if (index->version != 1)
	return error("Unsupported version for bitmap index file (%d)", index->version);

	/* Parse known bitmap format options */
	{
	uint32_t flags = ntohs(header->options);
	size_t cache_size = st_mult(index->pack->num_objects, sizeof(uint32_t));
	unsigned char *index_end = index->map + index->map_size - the_hash_algo->rawsz;

	if ((flags & BITMAP_OPT_FULL_DAG) == 0)
	return error("Unsupported options for bitmap index file "
	"(Git requires BITMAP_OPT_FULL_DAG)");

	if (flags & BITMAP_OPT_HASH_CACHE) {
	if (cache_size > index_end - index->map - header_size)
	return error("corrupted bitmap index file (too short to fit hash cache)");
	index->hashes = (void *)(index_end - cache_size);
	index_end -= cache_size;
	}
	}

	index->entry_count = ntohl(header->entry_count);
	index->map_pos += header_size;
	return 0;
	}

	static struct stored_bitmap store_bitmap(struct bitmap_index index,
	struct ewah_bitmap *root,
	const struct object_id *oid,
	struct stored_bitmap *xor_with,
	int flags)
	{
	struct stored_bitmap *stored;
	khiter_t hash_pos;
	int ret;

	stored = xmalloc(sizeof(struct stored_bitmap));
	stored->root = root;
	stored->xor = xor_with;
	stored->flags = flags;
	oidcpy(&stored->oid, oid);

	hash_pos = kh_put_oid_map(index->bitmaps, stored->oid, &ret);

	/* a 0 return code means the insertion succeeded with no changes,
	* because the SHA1 already existed on the map. this is bad, there
	* shouldn't be duplicated commits in the index */
	if (ret == 0) {
	error("Duplicate entry in bitmap index: %s", oid_to_hex(oid));
	return NULL;
	}

	kh_value(index->bitmaps, hash_pos) = stored;
	return stored;
	}

	static inline uint32_t read_be32(const unsigned char buffer, size_t pos)
	{
	uint32_t result = get_be32(buffer + *pos);
	(*pos) += sizeof(result);
	return result;
	}

	static inline uint8_t read_u8(const unsigned char buffer, size_t pos)
	{
	return buffer[(*pos)++];
	}

	#define MAX_XOR_OFFSET 160

	static int load_bitmap_entries_v1(struct bitmap_index *index)
	{
	uint32_t i;
	struct stored_bitmap *recent_bitmaps[MAX_XOR_OFFSET] = { NULL };

	for (i = 0; i < index->entry_count; ++i) {
	int xor_offset, flags;
	struct ewah_bitmap *bitmap = NULL;
	struct stored_bitmap *xor_bitmap = NULL;
	uint32_t commit_idx_pos;
	struct object_id oid;

	if (index->map_size - index->map_pos < 6)
	return error("corrupt ewah bitmap: truncated header for entry %d", i);

	commit_idx_pos = read_be32(index->map, &index->map_pos);
	xor_offset = read_u8(index->map, &index->map_pos);
	flags = read_u8(index->map, &index->map_pos);

	if (nth_packed_object_id(&oid, index->pack, commit_idx_pos) < 0)
	return error("corrupt ewah bitmap: commit index %u out of range",
	(unsigned)commit_idx_pos);

	bitmap = read_bitmap_1(index);
	if (!bitmap)
	return -1;

	if (xor_offset > MAX_XOR_OFFSET \|\| xor_offset > i)
	return error("Corrupted bitmap pack index");

	if (xor_offset > 0) {
	xor_bitmap = recent_bitmaps[(i - xor_offset) % MAX_XOR_OFFSET];

	if (xor_bitmap == NULL)
	return error("Invalid XOR offset in bitmap pack index");
	}

	recent_bitmaps[i % MAX_XOR_OFFSET] = store_bitmap(
	index, bitmap, &oid, xor_bitmap, flags);
	}

	return 0;
	}

	static char pack_bitmap_filename(struct packed_git p)
	{
	size_t len;

	if (!strip_suffix(p->pack_name, ".pack", &len))
	BUG("pack_name does not end in .pack");
	return xstrfmt("%.*s.bitmap", (int)len, p->pack_name);
	}

	static int open_pack_bitmap_1(struct bitmap_index bitmap_git, struct packed_git packfile)
	{
	int fd;
	struct stat st;
	char *idx_name;

	if (open_pack_index(packfile))
	return -1;

	idx_name = pack_bitmap_filename(packfile);
	fd = git_open(idx_name);
	free(idx_name);

	if (fd < 0)
	return -1;

	if (fstat(fd, &st)) {
	close(fd);
	return -1;
	}

	if (bitmap_git->pack) {
	warning("ignoring extra bitmap file: %s", packfile->pack_name);
	close(fd);
	return -1;
	}

	bitmap_git->pack = packfile;
	bitmap_git->map_size = xsize_t(st.st_size);
	bitmap_git->map = xmmap(NULL, bitmap_git->map_size, PROT_READ, MAP_PRIVATE, fd, 0);
	bitmap_git->map_pos = 0;
	close(fd);

	if (load_bitmap_header(bitmap_git) < 0) {
	munmap(bitmap_git->map, bitmap_git->map_size);
	bitmap_git->map = NULL;
	bitmap_git->map_size = 0;
	return -1;
	}

	return 0;
	}

	static int load_pack_bitmap(struct bitmap_index *bitmap_git)
	{
	assert(bitmap_git->map);

	bitmap_git->bitmaps = kh_init_oid_map();
	bitmap_git->ext_index.positions = kh_init_oid_pos();
	if (load_pack_revindex(bitmap_git->pack))
	goto failed;

	if (!(bitmap_git->commits = read_bitmap_1(bitmap_git)) \|\|
	!(bitmap_git->trees = read_bitmap_1(bitmap_git)) \|\|
	!(bitmap_git->blobs = read_bitmap_1(bitmap_git)) \|\|
	!(bitmap_git->tags = read_bitmap_1(bitmap_git)))
	goto failed;

	if (load_bitmap_entries_v1(bitmap_git) < 0)
	goto failed;

	return 0;

	failed:
	munmap(bitmap_git->map, bitmap_git->map_size);
	bitmap_git->map = NULL;
	bitmap_git->map_size = 0;

	kh_destroy_oid_map(bitmap_git->bitmaps);
	bitmap_git->bitmaps = NULL;

	kh_destroy_oid_pos(bitmap_git->ext_index.positions);
	bitmap_git->ext_index.positions = NULL;

	return -1;
	}

	static int open_pack_bitmap(struct repository *r,
	struct bitmap_index *bitmap_git)
	{
	struct packed_git *p;
	int ret = -1;

	assert(!bitmap_git->map);

	for (p = get_all_packs(r); p; p = p->next) {
	if (open_pack_bitmap_1(bitmap_git, p) == 0)
	ret = 0;
	}

	return ret;
	}

	struct bitmap_index prepare_bitmap_git(struct repository r)
	{
	struct bitmap_index bitmap_git = xcalloc(1, sizeof(bitmap_git));

	if (!open_pack_bitmap(r, bitmap_git) && !load_pack_bitmap(bitmap_git))
	return bitmap_git;

	free_bitmap_index(bitmap_git);
	return NULL;
	}

	struct include_data {
	struct bitmap_index *bitmap_git;
	struct bitmap *base;
	struct bitmap *seen;
	};

	struct ewah_bitmap bitmap_for_commit(struct bitmap_index bitmap_git,
	struct commit *commit)
	{
	khiter_t hash_pos = kh_get_oid_map(bitmap_git->bitmaps,
	commit->object.oid);
	if (hash_pos >= kh_end(bitmap_git->bitmaps))
	return NULL;
	return lookup_stored_bitmap(kh_value(bitmap_git->bitmaps, hash_pos));
	}

	static inline int bitmap_position_extended(struct bitmap_index *bitmap_git,
	const struct object_id *oid)
	{
	kh_oid_pos_t *positions = bitmap_git->ext_index.positions;
	khiter_t pos = kh_get_oid_pos(positions, *oid);

	if (pos < kh_end(positions)) {
	int bitmap_pos = kh_value(positions, pos);
	return bitmap_pos + bitmap_git->pack->num_objects;
	}

	return -1;
	}

	static inline int bitmap_position_packfile(struct bitmap_index *bitmap_git,
	const struct object_id *oid)
	{
	uint32_t pos;
	off_t offset = find_pack_entry_one(oid->hash, bitmap_git->pack);
	if (!offset)
	return -1;

	if (offset_to_pack_pos(bitmap_git->pack, offset, &pos) < 0)
	return -1;
	return pos;
	}

	static int bitmap_position(struct bitmap_index *bitmap_git,
	const struct object_id *oid)
	{
	int pos = bitmap_position_packfile(bitmap_git, oid);
	return (pos >= 0) ? pos : bitmap_position_extended(bitmap_git, oid);
	}

	static int ext_index_add_object(struct bitmap_index *bitmap_git,
	struct object object, const char name)
	{
	struct eindex *eindex = &bitmap_git->ext_index;

	khiter_t hash_pos;
	int hash_ret;
	int bitmap_pos;

	hash_pos = kh_put_oid_pos(eindex->positions, object->oid, &hash_ret);
	if (hash_ret > 0) {
	if (eindex->count >= eindex->alloc) {
	eindex->alloc = (eindex->alloc + 16) * 3 / 2;
	REALLOC_ARRAY(eindex->objects, eindex->alloc);
	REALLOC_ARRAY(eindex->hashes, eindex->alloc);
	}

	bitmap_pos = eindex->count;
	eindex->objects[eindex->count] = object;
	eindex->hashes[eindex->count] = pack_name_hash(name);
	kh_value(eindex->positions, hash_pos) = bitmap_pos;
	eindex->count++;
	} else {
	bitmap_pos = kh_value(eindex->positions, hash_pos);
	}

	return bitmap_pos + bitmap_git->pack->num_objects;
	}

	struct bitmap_show_data {
	struct bitmap_index *bitmap_git;
	struct bitmap *base;
	};

	static void show_object(struct object object, const char name, void *data_)
	{
	struct bitmap_show_data *data = data_;
	int bitmap_pos;

	bitmap_pos = bitmap_position(data->bitmap_git, &object->oid);

	if (bitmap_pos < 0)
	bitmap_pos = ext_index_add_object(data->bitmap_git, object,
	name);

	bitmap_set(data->base, bitmap_pos);
	}

	static void show_commit(struct commit commit, void data)
	{
	}

	static int add_to_include_set(struct bitmap_index *bitmap_git,
	struct include_data *data,
	struct commit *commit,
	int bitmap_pos)
	{
	struct ewah_bitmap *partial;

	if (data->seen && bitmap_get(data->seen, bitmap_pos))
	return 0;

	if (bitmap_get(data->base, bitmap_pos))
	return 0;

	partial = bitmap_for_commit(bitmap_git, commit);
	if (partial) {
	bitmap_or_ewah(data->base, partial);
	return 0;
	}

	bitmap_set(data->base, bitmap_pos);
	return 1;
	}

	static int should_include(struct commit commit, void _data)
	{
	struct include_data *data = _data;
	int bitmap_pos;

	bitmap_pos = bitmap_position(data->bitmap_git, &commit->object.oid);
	if (bitmap_pos < 0)
	bitmap_pos = ext_index_add_object(data->bitmap_git,
	(struct object *)commit,
	NULL);

	if (!add_to_include_set(data->bitmap_git, data, commit, bitmap_pos)) {
	struct commit_list *parent = commit->parents;

	while (parent) {
	parent->item->object.flags \|= SEEN;
	parent = parent->next;
	}

	return 0;
	}

	return 1;
	}

	static int should_include_obj(struct object obj, void _data)
	{
	struct include_data *data = _data;
	int bitmap_pos;

	bitmap_pos = bitmap_position(data->bitmap_git, &obj->oid);
	if (bitmap_pos < 0)
	return 1;
	if ((data->seen && bitmap_get(data->seen, bitmap_pos)) \|\|
	bitmap_get(data->base, bitmap_pos)) {
	obj->flags \|= SEEN;
	return 0;
	}
	return 1;
	}

	static int add_commit_to_bitmap(struct bitmap_index *bitmap_git,
	struct bitmap **base,
	struct commit *commit)
	{
	struct ewah_bitmap *or_with = bitmap_for_commit(bitmap_git, commit);

	if (!or_with)
	return 0;

	if (*base == NULL)
	*base = ewah_to_bitmap(or_with);
	else
	bitmap_or_ewah(*base, or_with);

	return 1;
	}

	static struct bitmap find_objects(struct bitmap_index bitmap_git,
	struct rev_info *revs,
	struct object_list *roots,
	struct bitmap *seen,
	struct list_objects_filter_options *filter)
	{
	struct bitmap *base = NULL;
	int needs_walk = 0;

	struct object_list *not_mapped = NULL;

	/*
	* Go through all the roots for the walk. The ones that have bitmaps
	* on the bitmap index will be `or`ed together to form an initial
	* global reachability analysis.
	*
	* The ones without bitmaps in the index will be stored in the
	* `not_mapped_list` for further processing.
	*/
	while (roots) {
	struct object *object = roots->item;
	roots = roots->next;

	if (object->type == OBJ_COMMIT &&
	add_commit_to_bitmap(bitmap_git, &base, (struct commit *)object)) {
	object->flags \|= SEEN;
	continue;
	}

	object_list_insert(object, &not_mapped);
	}

	/*
	* Best case scenario: We found bitmaps for all the roots,
	* so the resulting `or` bitmap has the full reachability analysis
	*/
	if (not_mapped == NULL)
	return base;

	roots = not_mapped;

	/*
	* Let's iterate through all the roots that don't have bitmaps to
	* check if we can determine them to be reachable from the existing
	* global bitmap.
	*
	* If we cannot find them in the existing global bitmap, we'll need
	* to push them to an actual walk and run it until we can confirm
	* they are reachable
	*/
	while (roots) {
	struct object *object = roots->item;
	int pos;

	roots = roots->next;
	pos = bitmap_position(bitmap_git, &object->oid);

	if (pos < 0 \|\| base == NULL \|\| !bitmap_get(base, pos)) {
	object->flags &= ~UNINTERESTING;
	add_pending_object(revs, object, "");
	needs_walk = 1;
	} else {
	object->flags \|= SEEN;
	}
	}

	if (needs_walk) {
	struct include_data incdata;
	struct bitmap_show_data show_data;

	if (base == NULL)
	base = bitmap_new();

	incdata.bitmap_git = bitmap_git;
	incdata.base = base;
	incdata.seen = seen;

	revs->include_check = should_include;
	revs->include_check_obj = should_include_obj;
	revs->include_check_data = &incdata;

	if (prepare_revision_walk(revs))
	die("revision walk setup failed");

	show_data.bitmap_git = bitmap_git;
	show_data.base = base;

	traverse_commit_list_filtered(filter, revs,
	show_commit, show_object,
	&show_data, NULL);

	revs->include_check = NULL;
	revs->include_check_obj = NULL;
	revs->include_check_data = NULL;
	}

	return base;
	}

	static void show_extended_objects(struct bitmap_index *bitmap_git,
	struct rev_info *revs,
	show_reachable_fn show_reach)
	{
	struct bitmap *objects = bitmap_git->result;
	struct eindex *eindex = &bitmap_git->ext_index;
	uint32_t i;

	for (i = 0; i < eindex->count; ++i) {
	struct object *obj;

	if (!bitmap_get(objects, bitmap_git->pack->num_objects + i))
	continue;

	obj = eindex->objects[i];
	if ((obj->type == OBJ_BLOB && !revs->blob_objects) \|\|
	(obj->type == OBJ_TREE && !revs->tree_objects) \|\|
	(obj->type == OBJ_TAG && !revs->tag_objects))
	continue;

	show_reach(&obj->oid, obj->type, 0, eindex->hashes[i], NULL, 0);
	}
	}

	static void init_type_iterator(struct ewah_iterator *it,
	struct bitmap_index *bitmap_git,
	enum object_type type)
	{
	switch (type) {
	case OBJ_COMMIT:
	ewah_iterator_init(it, bitmap_git->commits);
	break;

	case OBJ_TREE:
	ewah_iterator_init(it, bitmap_git->trees);
	break;

	case OBJ_BLOB:
	ewah_iterator_init(it, bitmap_git->blobs);
	break;

	case OBJ_TAG:
	ewah_iterator_init(it, bitmap_git->tags);
	break;

	default:
	BUG("object type %d not stored by bitmap type index", type);
	break;
	}
	}

	static void show_objects_for_type(
	struct bitmap_index *bitmap_git,
	enum object_type object_type,
	show_reachable_fn show_reach)
	{
	size_t i = 0;
	uint32_t offset;

	struct ewah_iterator it;
	eword_t filter;

	struct bitmap *objects = bitmap_git->result;

	init_type_iterator(&it, bitmap_git, object_type);

	for (i = 0; i < objects->word_alloc &&
	ewah_iterator_next(&filter, &it); i++) {
	eword_t word = objects->words[i] & filter;
	size_t pos = (i * BITS_IN_EWORD);

	if (!word)
	continue;

	for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
	struct object_id oid;
	uint32_t hash = 0, index_pos;
	off_t ofs;

	if ((word >> offset) == 0)
	break;

	offset += ewah_bit_ctz64(word >> offset);

	index_pos = pack_pos_to_index(bitmap_git->pack, pos + offset);
	ofs = pack_pos_to_offset(bitmap_git->pack, pos + offset);
	nth_packed_object_id(&oid, bitmap_git->pack, index_pos);

	if (bitmap_git->hashes)
	hash = get_be32(bitmap_git->hashes + index_pos);

	show_reach(&oid, object_type, 0, hash, bitmap_git->pack, ofs);
	}
	}
	}

	static int in_bitmapped_pack(struct bitmap_index *bitmap_git,
	struct object_list *roots)
	{
	while (roots) {
	struct object *object = roots->item;
	roots = roots->next;

	if (find_pack_entry_one(object->oid.hash, bitmap_git->pack) > 0)
	return 1;
	}

	return 0;
	}

	static struct bitmap find_tip_objects(struct bitmap_index bitmap_git,
	struct object_list *tip_objects,
	enum object_type type)
	{
	struct bitmap *result = bitmap_new();
	struct object_list *p;

	for (p = tip_objects; p; p = p->next) {
	int pos;

	if (p->item->type != type)
	continue;

	pos = bitmap_position(bitmap_git, &p->item->oid);
	if (pos < 0)
	continue;

	bitmap_set(result, pos);
	}

	return result;
	}

	static void filter_bitmap_exclude_type(struct bitmap_index *bitmap_git,
	struct object_list *tip_objects,
	struct bitmap *to_filter,
	enum object_type type)
	{
	struct eindex *eindex = &bitmap_git->ext_index;
	struct bitmap *tips;
	struct ewah_iterator it;
	eword_t mask;
	uint32_t i;

	/*
	* The non-bitmap version of this filter never removes
	* objects which the other side specifically asked for,
	* so we must match that behavior.
	*/
	tips = find_tip_objects(bitmap_git, tip_objects, type);

	/*
	* We can use the blob type-bitmap to work in whole words
	* for the objects that are actually in the bitmapped packfile.
	*/
	for (i = 0, init_type_iterator(&it, bitmap_git, type);
	i < to_filter->word_alloc && ewah_iterator_next(&mask, &it);
	i++) {
	if (i < tips->word_alloc)
	mask &= ~tips->words[i];
	to_filter->words[i] &= ~mask;
	}

	/*
	* Clear any blobs that weren't in the packfile (and so would not have
	* been caught by the loop above. We'll have to check them
	* individually.
	*/
	for (i = 0; i < eindex->count; i++) {
	uint32_t pos = i + bitmap_git->pack->num_objects;
	if (eindex->objects[i]->type == type &&
	bitmap_get(to_filter, pos) &&
	!bitmap_get(tips, pos))
	bitmap_unset(to_filter, pos);
	}

	bitmap_free(tips);
	}

	static void filter_bitmap_blob_none(struct bitmap_index *bitmap_git,
	struct object_list *tip_objects,
	struct bitmap *to_filter)
	{
	filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter,
	OBJ_BLOB);
	}

	static unsigned long get_size_by_pos(struct bitmap_index *bitmap_git,
	uint32_t pos)
	{
	struct packed_git *pack = bitmap_git->pack;
	unsigned long size;
	struct object_info oi = OBJECT_INFO_INIT;

	oi.sizep = &size;

	if (pos < pack->num_objects) {
	off_t ofs = pack_pos_to_offset(pack, pos);
	if (packed_object_info(the_repository, pack, ofs, &oi) < 0) {
	struct object_id oid;
	nth_packed_object_id(&oid, pack,
	pack_pos_to_index(pack, pos));
	die(_("unable to get size of %s"), oid_to_hex(&oid));
	}
	} else {
	struct eindex *eindex = &bitmap_git->ext_index;
	struct object *obj = eindex->objects[pos - pack->num_objects];
	if (oid_object_info_extended(the_repository, &obj->oid, &oi, 0) < 0)
	die(_("unable to get size of %s"), oid_to_hex(&obj->oid));
	}

	return size;
	}

	static void filter_bitmap_blob_limit(struct bitmap_index *bitmap_git,
	struct object_list *tip_objects,
	struct bitmap *to_filter,
	unsigned long limit)
	{
	struct eindex *eindex = &bitmap_git->ext_index;
	struct bitmap *tips;
	struct ewah_iterator it;
	eword_t mask;
	uint32_t i;

	tips = find_tip_objects(bitmap_git, tip_objects, OBJ_BLOB);

	for (i = 0, init_type_iterator(&it, bitmap_git, OBJ_BLOB);
	i < to_filter->word_alloc && ewah_iterator_next(&mask, &it);
	i++) {
	eword_t word = to_filter->words[i] & mask;
	unsigned offset;

	for (offset = 0; offset < BITS_IN_EWORD; offset++) {
	uint32_t pos;

	if ((word >> offset) == 0)
	break;
	offset += ewah_bit_ctz64(word >> offset);
	pos = i * BITS_IN_EWORD + offset;

	if (!bitmap_get(tips, pos) &&
	get_size_by_pos(bitmap_git, pos) >= limit)
	bitmap_unset(to_filter, pos);
	}
	}

	for (i = 0; i < eindex->count; i++) {
	uint32_t pos = i + bitmap_git->pack->num_objects;
	if (eindex->objects[i]->type == OBJ_BLOB &&
	bitmap_get(to_filter, pos) &&
	!bitmap_get(tips, pos) &&
	get_size_by_pos(bitmap_git, pos) >= limit)
	bitmap_unset(to_filter, pos);
	}

	bitmap_free(tips);
	}

	static void filter_bitmap_tree_depth(struct bitmap_index *bitmap_git,
	struct object_list *tip_objects,
	struct bitmap *to_filter,
	unsigned long limit)
	{
	if (limit)
	BUG("filter_bitmap_tree_depth given non-zero limit");

	filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter,
	OBJ_TREE);
	filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter,
	OBJ_BLOB);
	}

	static void filter_bitmap_object_type(struct bitmap_index *bitmap_git,
	struct object_list *tip_objects,
	struct bitmap *to_filter,
	enum object_type object_type)
	{
	if (object_type < OBJ_COMMIT \|\| object_type > OBJ_TAG)
	BUG("filter_bitmap_object_type given invalid object");

	if (object_type != OBJ_TAG)
	filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter, OBJ_TAG);
	if (object_type != OBJ_COMMIT)
	filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter, OBJ_COMMIT);
	if (object_type != OBJ_TREE)
	filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter, OBJ_TREE);
	if (object_type != OBJ_BLOB)
	filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter, OBJ_BLOB);
	}

	static int filter_bitmap(struct bitmap_index *bitmap_git,
	struct object_list *tip_objects,
	struct bitmap *to_filter,
	struct list_objects_filter_options *filter)
	{
	if (!filter \|\| filter->choice == LOFC_DISABLED)
	return 0;

	if (filter->choice == LOFC_BLOB_NONE) {
	if (bitmap_git)
	filter_bitmap_blob_none(bitmap_git, tip_objects,
	to_filter);
	return 0;
	}

	if (filter->choice == LOFC_BLOB_LIMIT) {
	if (bitmap_git)
	filter_bitmap_blob_limit(bitmap_git, tip_objects,
	to_filter,
	filter->blob_limit_value);
	return 0;
	}

	if (filter->choice == LOFC_TREE_DEPTH &&
	filter->tree_exclude_depth == 0) {
	if (bitmap_git)
	filter_bitmap_tree_depth(bitmap_git, tip_objects,
	to_filter,
	filter->tree_exclude_depth);
	return 0;
	}

	if (filter->choice == LOFC_OBJECT_TYPE) {
	if (bitmap_git)
	filter_bitmap_object_type(bitmap_git, tip_objects,
	to_filter,
	filter->object_type);
	return 0;
	}

	if (filter->choice == LOFC_COMBINE) {
	int i;
	for (i = 0; i < filter->sub_nr; i++) {
	if (filter_bitmap(bitmap_git, tip_objects, to_filter,
	&filter->sub[i]) < 0)
	return -1;
	}
	return 0;
	}

	/* filter choice not handled */
	return -1;
	}

	static int can_filter_bitmap(struct list_objects_filter_options *filter)
	{
	return !filter_bitmap(NULL, NULL, NULL, filter);
	}

	struct bitmap_index prepare_bitmap_walk(struct rev_info revs,
	struct list_objects_filter_options *filter,
	int filter_provided_objects)
	{
	unsigned int i;

	struct object_list *wants = NULL;
	struct object_list *haves = NULL;

	struct bitmap *wants_bitmap = NULL;
	struct bitmap *haves_bitmap = NULL;

	struct bitmap_index *bitmap_git;

	/*
	* We can't do pathspec limiting with bitmaps, because we don't know
	* which commits are associated with which object changes (let alone
	* even which objects are associated with which paths).
	*/
	if (revs->prune)
	return NULL;

	if (!can_filter_bitmap(filter))
	return NULL;

	/* try to open a bitmapped pack, but don't parse it yet
	* because we may not need to use it */
	CALLOC_ARRAY(bitmap_git, 1);
	if (open_pack_bitmap(revs->repo, bitmap_git) < 0)
	goto cleanup;

	for (i = 0; i < revs->pending.nr; ++i) {
	struct object *object = revs->pending.objects[i].item;

	if (object->type == OBJ_NONE)
	parse_object_or_die(&object->oid, NULL);

	while (object->type == OBJ_TAG) {
	struct tag tag = (struct tag ) object;

	if (object->flags & UNINTERESTING)
	object_list_insert(object, &haves);
	else
	object_list_insert(object, &wants);

	object = parse_object_or_die(get_tagged_oid(tag), NULL);
	object->flags \|= (tag->object.flags & UNINTERESTING);
	}

	if (object->flags & UNINTERESTING)
	object_list_insert(object, &haves);
	else
	object_list_insert(object, &wants);
	}

	/*
	* if we have a HAVES list, but none of those haves is contained
	* in the packfile that has a bitmap, we don't have anything to
	* optimize here
	*/
	if (haves && !in_bitmapped_pack(bitmap_git, haves))
	goto cleanup;

	/* if we don't want anything, we're done here */
	if (!wants)
	goto cleanup;

	/*
	* now we're going to use bitmaps, so load the actual bitmap entries
	* from disk. this is the point of no return; after this the rev_list
	* becomes invalidated and we must perform the revwalk through bitmaps
	*/
	if (load_pack_bitmap(bitmap_git) < 0)
	goto cleanup;

	object_array_clear(&revs->pending);

	if (haves) {
	revs->ignore_missing_links = 1;
	haves_bitmap = find_objects(bitmap_git, revs, haves, NULL,
	filter);
	reset_revision_walk();
	revs->ignore_missing_links = 0;

	if (haves_bitmap == NULL)
	BUG("failed to perform bitmap walk");
	}

	wants_bitmap = find_objects(bitmap_git, revs, wants, haves_bitmap,
	filter);

	if (!wants_bitmap)
	BUG("failed to perform bitmap walk");

	if (haves_bitmap)
	bitmap_and_not(wants_bitmap, haves_bitmap);

	filter_bitmap(bitmap_git, (filter && filter_provided_objects) ? NULL : wants,
	wants_bitmap, filter);

	bitmap_git->result = wants_bitmap;
	bitmap_git->haves = haves_bitmap;

	object_list_free(&wants);
	object_list_free(&haves);

	return bitmap_git;

	cleanup:
	free_bitmap_index(bitmap_git);
	object_list_free(&wants);
	object_list_free(&haves);
	return NULL;
	}

	static void try_partial_reuse(struct bitmap_index *bitmap_git,
	size_t pos,
	struct bitmap *reuse,
	struct pack_window **w_curs)
	{
	off_t offset, header;
	enum object_type type;
	unsigned long size;

	if (pos >= bitmap_git->pack->num_objects)
	return; /* not actually in the pack */

	offset = header = pack_pos_to_offset(bitmap_git->pack, pos);
	type = unpack_object_header(bitmap_git->pack, w_curs, &offset, &size);
	if (type < 0)
	return; /* broken packfile, punt */

	if (type == OBJ_REF_DELTA \|\| type == OBJ_OFS_DELTA) {
	off_t base_offset;
	uint32_t base_pos;

	/*
	* Find the position of the base object so we can look it up
	* in our bitmaps. If we can't come up with an offset, or if
	* that offset is not in the revidx, the pack is corrupt.
	* There's nothing we can do, so just punt on this object,
	* and the normal slow path will complain about it in
	* more detail.
	*/
	base_offset = get_delta_base(bitmap_git->pack, w_curs,
	&offset, type, header);
	if (!base_offset)
	return;
	if (offset_to_pack_pos(bitmap_git->pack, base_offset, &base_pos) < 0)
	return;

	/*
	* We assume delta dependencies always point backwards. This
	* lets us do a single pass, and is basically always true
	* due to the way OFS_DELTAs work. You would not typically
	* find REF_DELTA in a bitmapped pack, since we only bitmap
	* packs we write fresh, and OFS_DELTA is the default). But
	* let's double check to make sure the pack wasn't written with
	* odd parameters.
	*/
	if (base_pos >= pos)
	return;

	/*
	* And finally, if we're not sending the base as part of our
	* reuse chunk, then don't send this object either. The base
	* would come after us, along with other objects not
	* necessarily in the pack, which means we'd need to convert
	* to REF_DELTA on the fly. Better to just let the normal
	* object_entry code path handle it.
	*/
	if (!bitmap_get(reuse, base_pos))
	return;
	}

	/*
	* If we got here, then the object is OK to reuse. Mark it.
	*/
	bitmap_set(reuse, pos);
	}

	int reuse_partial_packfile_from_bitmap(struct bitmap_index *bitmap_git,
	struct packed_git **packfile_out,
	uint32_t *entries,
	struct bitmap **reuse_out)
	{
	struct bitmap *result = bitmap_git->result;
	struct bitmap *reuse;
	struct pack_window *w_curs = NULL;
	size_t i = 0;
	uint32_t offset;

	assert(result);

	while (i < result->word_alloc && result->words[i] == (eword_t)~0)
	i++;

	/* Don't mark objects not in the packfile */
	if (i > bitmap_git->pack->num_objects / BITS_IN_EWORD)
	i = bitmap_git->pack->num_objects / BITS_IN_EWORD;

	reuse = bitmap_word_alloc(i);
	memset(reuse->words, 0xFF, i * sizeof(eword_t));

	for (; i < result->word_alloc; ++i) {
	eword_t word = result->words[i];
	size_t pos = (i * BITS_IN_EWORD);

	for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
	if ((word >> offset) == 0)
	break;

	offset += ewah_bit_ctz64(word >> offset);
	try_partial_reuse(bitmap_git, pos + offset, reuse, &w_curs);
	}
	}

	unuse_pack(&w_curs);

	*entries = bitmap_popcount(reuse);
	if (!*entries) {
	bitmap_free(reuse);
	return -1;
	}

	/*
	* Drop any reused objects from the result, since they will not
	* need to be handled separately.
	*/
	bitmap_and_not(result, reuse);
	*packfile_out = bitmap_git->pack;
	*reuse_out = reuse;
	return 0;
	}

	int bitmap_walk_contains(struct bitmap_index *bitmap_git,
	struct bitmap bitmap, const struct object_id oid)
	{
	int idx;

	if (!bitmap)
	return 0;

	idx = bitmap_position(bitmap_git, oid);
	return idx >= 0 && bitmap_get(bitmap, idx);
	}

	void traverse_bitmap_commit_list(struct bitmap_index *bitmap_git,
	struct rev_info *revs,
	show_reachable_fn show_reachable)
	{
	assert(bitmap_git->result);

	show_objects_for_type(bitmap_git, OBJ_COMMIT, show_reachable);
	if (revs->tree_objects)
	show_objects_for_type(bitmap_git, OBJ_TREE, show_reachable);
	if (revs->blob_objects)
	show_objects_for_type(bitmap_git, OBJ_BLOB, show_reachable);
	if (revs->tag_objects)
	show_objects_for_type(bitmap_git, OBJ_TAG, show_reachable);

	show_extended_objects(bitmap_git, revs, show_reachable);
	}

	static uint32_t count_object_type(struct bitmap_index *bitmap_git,
	enum object_type type)
	{
	struct bitmap *objects = bitmap_git->result;
	struct eindex *eindex = &bitmap_git->ext_index;

	uint32_t i = 0, count = 0;
	struct ewah_iterator it;
	eword_t filter;

	init_type_iterator(&it, bitmap_git, type);

	while (i < objects->word_alloc && ewah_iterator_next(&filter, &it)) {
	eword_t word = objects->words[i++] & filter;
	count += ewah_bit_popcount64(word);
	}

	for (i = 0; i < eindex->count; ++i) {
	if (eindex->objects[i]->type == type &&
	bitmap_get(objects, bitmap_git->pack->num_objects + i))
	count++;
	}

	return count;
	}

	void count_bitmap_commit_list(struct bitmap_index *bitmap_git,
	uint32_t commits, uint32_t trees,
	uint32_t blobs, uint32_t tags)
	{
	assert(bitmap_git->result);

	if (commits)
	*commits = count_object_type(bitmap_git, OBJ_COMMIT);

	if (trees)
	*trees = count_object_type(bitmap_git, OBJ_TREE);

	if (blobs)
	*blobs = count_object_type(bitmap_git, OBJ_BLOB);

	if (tags)
	*tags = count_object_type(bitmap_git, OBJ_TAG);
	}

	struct bitmap_test_data {
	struct bitmap_index *bitmap_git;
	struct bitmap *base;
	struct progress *prg;
	size_t seen;
	};

	static void test_show_object(struct object object, const char name,
	void *data)
	{
	struct bitmap_test_data *tdata = data;
	int bitmap_pos;

	bitmap_pos = bitmap_position(tdata->bitmap_git, &object->oid);
	if (bitmap_pos < 0)
	die("Object not in bitmap: %s\n", oid_to_hex(&object->oid));

	bitmap_set(tdata->base, bitmap_pos);
	display_progress(tdata->prg, ++tdata->seen);
	}

	static void test_show_commit(struct commit commit, void data)
	{
	struct bitmap_test_data *tdata = data;
	int bitmap_pos;

	bitmap_pos = bitmap_position(tdata->bitmap_git,
	&commit->object.oid);
	if (bitmap_pos < 0)
	die("Object not in bitmap: %s\n", oid_to_hex(&commit->object.oid));

	bitmap_set(tdata->base, bitmap_pos);
	display_progress(tdata->prg, ++tdata->seen);
	}

	void test_bitmap_walk(struct rev_info *revs)
	{
	struct object *root;
	struct bitmap *result = NULL;
	size_t result_popcnt;
	struct bitmap_test_data tdata;
	struct bitmap_index *bitmap_git;
	struct ewah_bitmap *bm;

	if (!(bitmap_git = prepare_bitmap_git(revs->repo)))
	die("failed to load bitmap indexes");

	if (revs->pending.nr != 1)
	die("you must specify exactly one commit to test");

	fprintf(stderr, "Bitmap v%d test (%d entries loaded)\n",
	bitmap_git->version, bitmap_git->entry_count);

	root = revs->pending.objects[0].item;
	bm = bitmap_for_commit(bitmap_git, (struct commit *)root);

	if (bm) {
	fprintf(stderr, "Found bitmap for %s. %d bits / %08x checksum\n",
	oid_to_hex(&root->oid), (int)bm->bit_size, ewah_checksum(bm));

	result = ewah_to_bitmap(bm);
	}

	if (result == NULL)
	die("Commit %s doesn't have an indexed bitmap", oid_to_hex(&root->oid));

	revs->tag_objects = 1;
	revs->tree_objects = 1;
	revs->blob_objects = 1;

	result_popcnt = bitmap_popcount(result);

	if (prepare_revision_walk(revs))
	die("revision walk setup failed");

	tdata.bitmap_git = bitmap_git;
	tdata.base = bitmap_new();
	tdata.prg = start_progress("Verifying bitmap entries", result_popcnt);
	tdata.seen = 0;

	traverse_commit_list(revs, &test_show_commit, &test_show_object, &tdata);

	stop_progress(&tdata.prg);

	if (bitmap_equals(result, tdata.base))
	fprintf(stderr, "OK!\n");
	else
	die("mismatch in bitmap results");

	free_bitmap_index(bitmap_git);
	}

	int test_bitmap_commits(struct repository *r)
	{
	struct bitmap_index *bitmap_git = prepare_bitmap_git(r);
	struct object_id oid;
	MAYBE_UNUSED void *value;

	if (!bitmap_git)
	die("failed to load bitmap indexes");

	kh_foreach(bitmap_git->bitmaps, oid, value, {
	printf("%s\n", oid_to_hex(&oid));
	});

	free_bitmap_index(bitmap_git);

	return 0;
	}

	int rebuild_bitmap(const uint32_t *reposition,
	struct ewah_bitmap *source,
	struct bitmap *dest)
	{
	uint32_t pos = 0;
	struct ewah_iterator it;
	eword_t word;

	ewah_iterator_init(&it, source);

	while (ewah_iterator_next(&word, &it)) {
	uint32_t offset, bit_pos;

	for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
	if ((word >> offset) == 0)
	break;

	offset += ewah_bit_ctz64(word >> offset);

	bit_pos = reposition[pos + offset];
	if (bit_pos > 0)
	bitmap_set(dest, bit_pos - 1);
	else /* can't reuse, we don't have the object */
	return -1;
	}

	pos += BITS_IN_EWORD;
	}
	return 0;
	}

	uint32_t create_bitmap_mapping(struct bitmap_index bitmap_git,
	struct packing_data *mapping)
	{
	uint32_t i, num_objects;
	uint32_t *reposition;

	num_objects = bitmap_git->pack->num_objects;
	CALLOC_ARRAY(reposition, num_objects);

	for (i = 0; i < num_objects; ++i) {
	struct object_id oid;
	struct object_entry *oe;

	nth_packed_object_id(&oid, bitmap_git->pack,
	pack_pos_to_index(bitmap_git->pack, i));
	oe = packlist_find(mapping, &oid);

	if (oe)
	reposition[i] = oe_in_pack_pos(mapping, oe) + 1;
	}

	return reposition;
	}

	void free_bitmap_index(struct bitmap_index *b)
	{
	if (!b)
	return;

	if (b->map)
	munmap(b->map, b->map_size);
	ewah_pool_free(b->commits);
	ewah_pool_free(b->trees);
	ewah_pool_free(b->blobs);
	ewah_pool_free(b->tags);
	kh_destroy_oid_map(b->bitmaps);
	free(b->ext_index.objects);
	free(b->ext_index.hashes);
	bitmap_free(b->result);
	bitmap_free(b->haves);
	free(b);
	}

	int bitmap_has_oid_in_uninteresting(struct bitmap_index *bitmap_git,
	const struct object_id *oid)
	{
	return bitmap_git &&
	bitmap_walk_contains(bitmap_git, bitmap_git->haves, oid);
	}

	static off_t get_disk_usage_for_type(struct bitmap_index *bitmap_git,
	enum object_type object_type)
	{
	struct bitmap *result = bitmap_git->result;
	struct packed_git *pack = bitmap_git->pack;
	off_t total = 0;
	struct ewah_iterator it;
	eword_t filter;
	size_t i;

	init_type_iterator(&it, bitmap_git, object_type);
	for (i = 0; i < result->word_alloc &&
	ewah_iterator_next(&filter, &it); i++) {
	eword_t word = result->words[i] & filter;
	size_t base = (i * BITS_IN_EWORD);
	unsigned offset;

	if (!word)
	continue;

	for (offset = 0; offset < BITS_IN_EWORD; offset++) {
	size_t pos;

	if ((word >> offset) == 0)
	break;

	offset += ewah_bit_ctz64(word >> offset);
	pos = base + offset;
	total += pack_pos_to_offset(pack, pos + 1) -
	pack_pos_to_offset(pack, pos);
	}
	}

	return total;
	}

	static off_t get_disk_usage_for_extended(struct bitmap_index *bitmap_git)
	{
	struct bitmap *result = bitmap_git->result;
	struct packed_git *pack = bitmap_git->pack;
	struct eindex *eindex = &bitmap_git->ext_index;
	off_t total = 0;
	struct object_info oi = OBJECT_INFO_INIT;
	off_t object_size;
	size_t i;

	oi.disk_sizep = &object_size;

	for (i = 0; i < eindex->count; i++) {
	struct object *obj = eindex->objects[i];

	if (!bitmap_get(result, pack->num_objects + i))
	continue;

	if (oid_object_info_extended(the_repository, &obj->oid, &oi, 0) < 0)
	die(_("unable to get disk usage of %s"),
	oid_to_hex(&obj->oid));

	total += object_size;
	}
	return total;
	}

	off_t get_disk_usage_from_bitmap(struct bitmap_index *bitmap_git,
	struct rev_info *revs)
	{
	off_t total = 0;

	total += get_disk_usage_for_type(bitmap_git, OBJ_COMMIT);
	if (revs->tree_objects)
	total += get_disk_usage_for_type(bitmap_git, OBJ_TREE);
	if (revs->blob_objects)
	total += get_disk_usage_for_type(bitmap_git, OBJ_BLOB);
	if (revs->tag_objects)
	total += get_disk_usage_for_type(bitmap_git, OBJ_TAG);

	total += get_disk_usage_for_extended(bitmap_git);

	return total;
	}

	const struct string_list bitmap_preferred_tips(struct repository r)
	{
	return repo_config_get_value_multi(r, "pack.preferbitmaptips");
	}

git / git

git/pack-bitmap.c